2016 YZ450 Engine Noise

Haha. Well, I found the same thing... When my noise came about, it was after it had boiled over. But I didn't think I lost much coolant. The same trip, I crushed my left radiator.

I never thought to check the water level, but never thought low water would be a symptom of that noise.

So when I pulled the radiator, I noticed the level was low, about 3/4q ( which is about half-ish empty ). I straightened out the rad, re installed and noticed while doing my leak check, the noise was gone... ?

So I took it to a woods race and mx track this weekend... No noise.



Very likely I'm sure. Prob not enough to do any damage, but I plan on bringing my borescope home this weekend and doing some looking around.

I did a leak down check on my bike today at top dead center 100 psi, the valves were ok however I was getting a little of air past the rings. Do you guys think this is normal or not enough to be concerned about?


Rings have gaps at the ends.  They'll always leak,  What was the percentage leaked?

Had a bad regulator on the first test couldn't figure percentage lost. With the new regulator I'm at 3% to 5% loss witch is good. I've got it all back together and switch the coolant to engine ice so see what it does next time I take it out.

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